Delirium is one of several geriatric syndromes, and is among the most common postoperative complications, affecting up to 70% of surgical patients older than 60. Delirium is an acute change that manifests as inattention and inability to think logically, and is deeply distressing to patients and their families. Based on our surveys of 1,000 surgical patients, over 30% were worried about experiencing delirium. Delirious patients are unable to participate effectively in rehabilitation exercises and are susceptible to other geriatri syndromes, like falls. The occurrence and duration of delirium are associated with longer intensive care unit and hospital stay, persistent cognitive deterioration, hospital readmission and increased mortality rate. Additionally, delirium carries a huge social and economic burden, costing over $60,000 per patient per year. Despite the importance of delirium to patients and to society, no approach has been proven to prevent postoperative delirium. Furthermore postoperative delirium is frequently unrecognized, and surgical patients are not followed systematically after they are discharged from hospital. Without diagnosing delirium or following patients postoperatively, we are limited in our ability to test the effectiveness of any interventin to prevent or treat postoperative delirium and its sequelae. There is mounting evidence that electroencephalography guidance of general anesthesia can decrease postoperative delirium. Specifically, our group has found that a suppressed electroencephalogram pattern, which occurs with deep anesthesia, is associated with increased delirium and death after surgery. The Electroencephalograph Guidance of Anesthesia to Alleviate Geriatric Syndromes (ENGAGES) Study will therefore compare the effectiveness of two anesthetic protocols for reduction of postoperative delirium. One protocol will be based on current standard anesthetic practice, and the other protocol will be based on electroencephalography guidance. We also expect to determine the impact of the anesthetic protocols on patient reported outcomes of health-related quality of life. At Washington University, we have successfully implemented an ambitious study that enrolls patients at the preoperative assessment clinic, and tracks their health and wellbeing at 30 days and at 1-year postoperatively. This will enable us to assess the consequences of postoperative delirium and to determine whether anesthetic management can impact patient reported outcomes, such as health-related quality of life. We shall also explore whether a multi-component safety intervention for delirious patients prevents downstream adverse events, like falls. The ENGAGES study - through its structured anesthesia protocols, its thorough approach to delirium assessment, and its ability to track patients' health and well-being postoperatively - s poised to make a major contribution to the care of elderly patients who are at risk of postoperative delirium and other adverse outcomes.